The invention refers to a knife arrangement for a granulator for granulating plastic ropes with two draw-in rollers and a cutting rotor cooperating with a counter-knife and a stripper opposing one of the draw-in rollers, whereby counter-knife and stripper are mounted on a common support, the stripper is arranged adjustably for adjusting the distance between the stripper and the draw-in roller, and the stripper has a support surface for feeding the plastic ropes to the counter-knife and to the cutting rotor, and is provided on its one side with a stripping edge facing the draw-in roller, and on its other side with an end edge facing the counter-knife.
Such knife arrangements are in permanent use. With these, the stripper is adapted to be displaced into the direction of the corresponding draw-in roller due to a corresponding fastening on the support, whereby it moves away from the counter-knife. Such a displacement is, e.g., necessary, if the cutting rotor and the counter-knife have to be resharpened due to wear, leading also to a displacement of the stripper relative to its associated draw-in roller. To recover the original relative position of draw-in roller and stripper, the stripper has to be displaced accordingly in the direction towards the draw-in roller.
The invention is based on the object, to configure the knife arrangement with the stripper such that during displacement of the stripper carrying at the same time above itself plastic ropes which are fed to the counter-knife, to keep its support surface serving for this in such a relative position to the counter-knife that the function of the support surface is practically preserved whereby the supply of the ropes to the counter-knife is not influenced by an adjustment of the stripper.
According to the invention, this results from the support having a support surface facing the stripper on which the stripper rests with a counter surface adapted to one of the support surfaces, whereby support surface and counter surface approach each other in the direction towards the counter-knife in a wedge-shaped manner, that the end edge is formed like a cutting edge, and the stripper, together with the support, reaches the counter-knife essentially continuously.
Due to the support surface and the correspondingly formed counter surface of the stripper with its cutting edge-like tapering end edge facing the counter-knife, a guidance of the plastic ropes results during displacement of the stripper, which thereby are supported on a base which, during displacement of the stripper, forms a slight kink only in cross-sectional view without gap formation, such that the guidance of the plastic ropes remains totally uninfluenced by a displacement of the stripper. Thereby, the advantageous property results that due to the cutting edge like tapering end edge of the stripper, also during its displacement away from the counter-knife, practically no gap and no spacing, respectively, is formed in the area between the end edge and the counter-knife, in which dust, dirt, and also plastic material can be accumulated, leading to an impairment of the uniform guidance of the plastic ropes over the stripper. The also makes a special cleaning in the area of the stripper and counter-knife superfluous, which is especially important in a continuous operation of a granulator.
Advantageously, the support and the stripper are constructed such that the support surface has a curvature running in a circular shape in cross-section, and the counter surface of the stripper has the same radius as the support surface. The guidance of the stripper during its displacement can be constructed in an advantageous manner as rotation around an axis, coinciding approximately with the center of the arc of a circle defining the support surface.
It is also possible to construct the support surface and the counter surface such that both run planar which is particularly advantageous with respect to manufacturing techniques.